Braking mechanism



Feb. 16, 1937.

R. MELVILLE BRAKING MECHANISM Filed May 22, 1"

3 Sheets-Sheet 1 Z8 48 Z9 .50 l/ 2/, lllllllLllll H .l

INVENTOR -ROBERT MEL V/LLE 23 BY ATTORNEYS Feb. 16, 1937. R MELVILLE 2,070,614

BRAKING MECHANISM Filed May 22, 1955 3 Sheets$heet 2 nv VEN TOR 3 ROBERT MEL V/LLE ATTORNEYS w' Feb. 16,1937. R, MELWLLE 2,070,614

BRAKING MECHANISM Filed May 22, 1935 3 Sheets-Sheet 5 6 GI 2 ZZbU3Z33 ZZa' Z5 IN VENT-OR ROBERT MEL V/LLE a, g; y

A TORNEY Patented Feb. 16, 1937 UNITED STATES PATENT OFFICE- BRAKING MECHANISM Robert Melville, Challis, Idaho Application May 22, 1935, Serial No. 22,873

8 Claims.

This application is a continuation in part of my application Serial No. 721,783, filed April 21, 1934.

The invention relates generally to braking systems, and more particularly to fluid brake mechanisms.

An object of this invention is to provide a novel fluid brake mechanism by which any amount of braking force from a minimum to a maximum can be eflected with the utmost ease by varying the displacement of fluid within a sealed chamber in such manner that the fluid will coact with a gear train in creating the braking force upon a driven element to be braked.

Another object of this invention is to provide a novel fluid brake mechanism capable of a wide range of use and which is absolutely positive in action to create an extremely powerful braking force up to a complete locking of a driven element against rotation and to provide a full release of such element to entirely eliminate any frictional drag upon the element, all the while enabling a braking application to be smoothly graduated in intensity from a minimum to a maximum or vice versa.

Another object of the invention is to provide in a brake mechanism of the above described character, a means which automatically func tions to synchronize the speeds of toothed driven and control members prior to meshing the teeth to create the braking force, whereby to prevent clashing of the teeth with the attendant wear of and damage to the teeth.

Another object of the invention is to provide a fluid brake mechanism which is equally efiicient in the braking of a rotary driven element irrespective of the direction of rotation of the element.

Another object of this invention is to provide a novel fluid braking mechanism embodying extremely simple means for varying the amount of fluid displacement and hence the intensity of the braking force, and wherein variations in internal and external pressures induced by temperature changes is automatically compensated for, so that the attendant variations in the volume of liquid within the sealed chamber of the mechanism will not burst the chamber or cause inefficient operation.

Other objects and advantages will appear from the following specifications.

In the drawings:

Figure 1 is a plan view showing one form of fluid brake mechanism embodying this invention and applied to a motor vehicle; a v a Figure 2 is an enlarged vertical axial sectional view taken on the line 2--2 of Figure 1 and illustrating the fully released position of the mechanism;

Figure 3 is a fragmentary view of a portion of 5 the mechanism shown in Figure 2, and illustrat ing the synchronizing means in operation; I

Figure 4 is a vertical transverse sectional view taken on the line 44 of Figure 2, and with a portion of the gear housing broken away to show 0 gearing therein;

Figure 5 is an enlarged fragmentary sectional view illustrating the position of the mechanism to obtain partial braking;

Figure 6 is a transverse sectional view taken 15 on the line 6--6 of Figure 5;

Figure 7 is a view similar to Figure 5, and illustrating the position of the mechansm to obtain maximum braking; v i

Figure 8 is a transverse sectional view taken on the line 8- -8 of Figure 7.

Reference will be first had particularly to Figures 1 to 8, inclusive. I

In carrying the invention into practice, a generally circular housing H is provided and is composed of two sections I0 and I I suitably secured together by bolts I2 (Figure 4). These sections coact to define a liquid chamber I 3; and a driven element, in this instance the propeller shaft I4 of a motor vehicle (Figure 1), extends axially through the sections and the intervening chamber, suitable packing glands I5 and I6 surrounding the shaft and coacting therewith and with the sections to prevent the leakage of liquid from the chamber around the shaft.

The housing H is rigidly supported on the chassis C so as to bestationary or non-rotatable with respect thereto. For this, purpose a suitable cross member I! is provided in the chassis frame I8, to which the housing is secured by fastening 7 members I 9, all as shown in Figure 1.

Fixed to the shaft I4 by a key 20 so as to closely fit within the central portion of the chamber I3 is a gear 2| which thus constitutes a part of the aforestated driven element for positive rota- 45 tion with the shaft. The teeth of the gear 2| are stepped in a manner to form portions 2 I a, 2 lb and 2| 0 of progressively different diameters which are complementarily related to the stepped teeth of each of a plurality of pinion gears 22 adapted to be simultaneously adjusted from the non-meshing position shown in Figure 2 through the partially meshed position shown in Figure 5, to the fully meshed position shown in Figures 7 and 8, or vice versa; all \for the purpose of varyv ing the displacement of liquid in the chamber [3, with corresponding variation in the braking force applied to the shaft I4.v In order to simplify manufacture of the gears 2| and 22 they are preferably made in sections as shown in Figures 2 and 5, which sections can be welded or otherwise rigidly secured together to form unitary structures. 7 r

At the smaller end of each of the pinion gears is fixed, concentrically thereof,a ring22a of yieldable material-such as rubber, which is of a diameter to ride over the teeth of the portion Zlq. of the gear 2| as the pinion gears are acljusted from the non-meshing position shown-in" trated in the present embodiment are arranged at equ lly spac dp ints.circum r all e t V thlir engear .2. |..-anq eeehconstitutes a pa of a control .unit U. As the several'control units arepnide itical icon truct onfia detai de c ption of one unit will-suflice for all; V H

I 'Each gear-2 2,is .iournaledto freely: rotate upon a shifter shaft 23 between collars 24. and 25; fixed to-the shaft. Theshaftx23 is non-rotatable and ismounted ni -packing glands-26 and for axial adjustment to'correspondingly shiftfthe gear 22 1 532693 very its in hing relationship with V the gear 2|. 'Each of :gfib-Bcgears 22 operates ;in

v aradial enlargernent of the chamber I 3 forming an auxiliary; chamber I3astepped to correspond passages 22b throughivvh-ieh l iqui'd in the chamber with. the stepped form of the. gear;22, .and is pror des; with ezei euierg ries i x allyfe tendin w ibeifreeto-b epa sain he auxiiieryc from. one side of the gean totheotherlas shifting 1e; Pflflkill g1aI12b0fLeachgunit is-supported by a .eover-plate 28 secured by bolts 29 to a cylinsdl 1:2 @nS-i0n.efgthesection'll.so'as to close 'the-epeniendef the extension through which the Q i-isiadaptedzto be passed into the chamber 13 magsembling thezmechanism. gThes'teethof ;th largest steppffthegear 22jterminate short of Lcm'lesponding -end1iof=,the's-gear .so that the peripheral portion .of such; end formsa continuoussiian e zzc andqhas a runningqfit within the .bore of the. extension. A fluid; suclizas glyc'erine, -1Qa3tOn0ilaorother liquid, is supplied tofthe chamherriirthrough a fillingopening 30 controlled by aplug 53] to completely; fill alliunoocupied s'pace in the chamberwand in order tocompensate for variationsein;thefivolume of theliquid caus'e'd by 7 temperature changes :or from other so'urcesgyone or more flei'cibleidiaphragms 5 32' spans a port 33 infthe wall of the chamber, and'is. confined ia'gainst displacement byaretaining ring'34 so zthat .th :fdiaphragm will at all times-be exposed stor-the'liquidinthe ehamber. a 1,heshifter-shafts 23of the-several units U iarel adapted to'be'simultaneously and correspondairigly .xactuated 'rbyila fo'ot' pedal :2 35 extending through aislot36 -inithe floor board3l of the vehicle .2.1111 *being pivotally-connecte'd at :38 to V the free end. of azlever'i 3flgfixed to. a rock shaft 4.0 rjournaled :in bearingsA l....l4l on the chassis braking action upo-n the shaft.

frame I 8 and in a center bearing 42 on the transmission casing 43. At opposite sides of the bearing 42 arms 44-44 are fixed to the rock shaft 49 and are pivotally connected to links 45'45 pivoted at'46-46 to a collar 41 freely mounted on the shaft l4. 7

A spider 48 having four equally spaced arms connected respectively at 49 to the shifter shafts 23 is provided with a hub 50 freely receiving the shaft 14. A ball thrust bearing 5i is interposed between thecollar fl andthe hub vlit-of-the spider 48 for coaction therewith upon depression of the pedal 35, in shifting the several pinion gears 23 from non-meshing to meshing positions relative to -zthegear 22, against the action of a coil spring .52.. surrounding the shaft l4 and abutting the hub-"Wand the nut of the packing gland It, all j as clearly shown in Figure 2. 7

One longitudinal edge of the pedal arms 35 is=-provided with a series of notches 54, any one of which-is adapted-to reoeive.- .a ;-fixed .detenti-S projecting into? the Eslot 3 6; A ball 56 engaged by a follower block 51 mounted in the bore 58 0f .the floor-board structure is urged by a coil spring .59 .to ride upon the opposite longitudinal edge ofthe arm 53 so as to releasably retain the arm in latching-engagement with the detent-fiiand thereby -rnaintain the gears; 22, in the positions towliich they; are adjusted, yet permit the arm tobe-readily released upon rocking thearm about .thepivot 38' sufficiently for the arm to clear the detent.

The operation of the-braking mechanism is 4' follows: V 1

Let-itbe assumed th tftherequisite amount of liquid hasbeen supplied to the chamberil3; and the I auxiliary chambers .I 3a. 'and;;that the, pinion gears- 22 occupy the non-meshing .orreleasedi-positionqshown in FigureyZ- Inthis positionrof am justment; with-thegpin-ion gears -22 clear of the t driven gear :21, the latterwill be free to rotate in the chamber 1 3,: due to the fact that allrliquid containedwin the spaces between its teeth ,and

' the.peripheralrwalljfifigofythis chamber intermediate the auxiliary chambers I3a will b90213.

:riedaround with the driven gear, thus permitting freehand unobstructed rotation of the. latter by the shaft |4..so that; no braking of .theishaft occurs. W q j However, as the pedal 35 is depressed to simultaneously advance the several pinion'gears 22 7 into mesh with thedriving gear 2 I following the action of the'respectivesynchronizing rings 22a 'in bringing the speeds of the pinion gears .up to that of the drivinggear, displacement of. liquid from between the meshingteeth 'commenc'esand increases as the .pinion'gears are advanced fur- This disa placement of liquid creates a force resisting rotation ofthe-piniodgears about their respe'ctive ther into mesh with the driven gear.

axes ,whichresistance isapplied through the driven'gear2l .toJtheshaft'M insetting up a force naturally increases as thedisplacement of 7 liquid increases fromthe initial meshing of the; gearsxthrough the partial meshing thereof shown irrFigures Band 6 to the'full meshing of the gears This *b raking shown in Figure '7 and 8,whereincommunication between the chamber l3 and the auxiliary chain-j bers' l3a iscompletely disrupted so-that the'relatively non-compressible liquid trapped'in the 'spacesbetween the teeth of the driven gear 2| "will coactswith the meshing-teeth of the pinion ;gears 22- inlpreventing rotation of the latter. As

the housing in which-,thezpinion gearsarejour- 15 naled is stationary, and as the pinion gears are held by the trapped liquid against rotation about their respective axes as aforestated, it will be evident that the driven gear 2| and hence the driven shaft M will be locked against rotation, which constitutes the maximum braking action possible.

It will thus be manifest that the braking action upon the shaft 14 increases or decreases according as the displacement of liquid is increased or decreased by varying the meshed relationship of the pinion gears and the driven gear. The provision of the relatively large gear 2| and the relatively small pinion gears has the mechanical effect of producing great leverage so that the braking action is very powerful and can be obtained with but negligible manual effort.

Furthermore, the mechanism provides a brake for any power driven shaft, which will function with equal efficiency irrespective of the direction in which the shaft is rotating.

I claim:

1. Braking mechanism comprising a non-rotatable housing defining a liquid containing chamber; a driven gear rotatably mounted in said chamber; a plurality of shifter shafts arranged at circumferentially spaced points about the axis of the driven gear andextending into the chamber; control gears rotatably mounted on said shafts in the chamber and shiftable therewith to occupy a non-meshing position and various meshing positions with respect to said driven gear for coaction with the latter in varying the displacement of liquid in said chamber to accordingly vary the braking force applied to the driven gear; and means for simultaneously and correspondingly actuating the shifter shafts.

2. Braking mechanism comprising a fixed housing defining a central liquid containing chamber and a plurality of circumferentially spaced auxiliary liquid containing chambers arranged about said central chamber and in communication therewith; a driven gear rotatably mounted in said central chamber; gears rotatably mounted in said auxiliary chambers; said driven gear and the last mentioned gears being relatively shiftable axially to various meshed positions for 00- action in varying the displacement of liquid in the chambers to accordingly vary the braking force applied to the driven gear; and actuating means for the relatively shiftable gearing.

3. Braking mechanism comprising a non-rotatable housing containing a body of liquid; power transferring mechanism operating in the body of liquid, and including a driven gear and a pinion gear rotatably mounted and relatively shiftable axially to various meshed positions for coaction in varying the displacement of liquid in the housing to accordingly vary the braking force applied to the driven gear; means for urging the shiftable gear to non-meshing position; means for moving the shiftable gear to various meshing positions; and means for releasably retaining the shiftable gear in any position to which it is adjustable.

4. Braking mechanism comprising a fixed housing defining a central liquid containing chamber and a plurality of circumferentially spaced auxiliary liquid containing chambers arranged about said central chamber and in communication therewith; a driven gear rotatably mounted in said central chamber; gears rotatably mounted in said auxiliary chambers; said driven gear and the last mentioned gears being relatively shifttion and various meshed positions; means for causing such displacement of liquid in the housing as the gears are meshed and unmeshed that the liquid will set up a braking force on said gears varying in intensity in accordance with the extent to which the gears are meshed; and means for synchronizing the speeds of the gears prior to meshing so as to prevent clashing of the teeth of the gears when brought into mesh.

6. Braking mechanism comprising a fixed housing containing a body of liquid; co-operable gears operating in the body of liquid and relatively adjustable to occupy a non-meshing position and various meshed positions; means for causing such displacement of liquid in the housing as the gears are meshed and unmeshed that the liquid will set up a braking force on said gears varying in intensity in accordance with the extent to which the gears are meshed; and means providing a frictional surface on one of said gears arranged to be brought into driving engagement with another of said gears prior to meshing the gears so as to synchronize the speeds of the gears for the purpose described.

7. Braking mechanism comprising a non-rotatable housing containing a body of liquid; power transferring mechanism operating in the body of liquid and including a driven gear and a pinion gear rotatably mounted and relatively shiftable from a position wherein they are out of mesh to various meshed positions for coaction in varying the displacement of liquid in the housing to accordingly vary the braking force ap plied to the driven gear; means for actuating the shiftable gear; and means correlated with the gears for synchronizing the speed of the pinion gear with that of the driven gear prior to meshing the gears so as to prevent clashing the teeth of the gears when brought into mesh.

8. Braking mechanism comprising a non-rotatable housing containing a body of liquid; power transferring mechanism operating in' the body of liquid and including a driven gear and a pinion gear rotatably mounted and relatively shiftable axially from a position wherein they are out of mesh to various meshed positions for coaction in varying the displacement of liquid'in the housing to accordingly vary the braking force applied to the driven gear; means foractuating the shiftable gear; and means providing an annular friction surface on one of said gears disposed to be brought into peripheral contact with the other of said gears prior to meshing the gears, for coaction in equalizing the peripheral speeds of the gears in order to prevent clashing the teeth of the gears.

ROBERT MELVILLE. 

